Seals for collets



United States Patent [72] Inventor Hubert J. Parsons 2,448,423 8/1948Dodge 279/1(ME)UX Horseheads, New York 2,557,301 6/1951 Lundy 279/1 gr m3 1 3 2 FOREIGN PATENTS i e c Patented Nov. 10,1970 482,766 1938 GreatBritain ..279/l(ME)UX [73] Assignee Hardinge Brothers, Inc. PrimaryExaminer-Robert C. Riordon Elmira, New York Assistant ExaminerDonald D.Evenson Attorney-Shlesinger, Arkwright and Garvey [54] SEALS FOR COLLETS7 Claims, 10 Drawing Figs.

[52] U.S.Cl 279/51 BS This disclosure relates to collets of the type[51] Int. Cl. B23b 25/04, commonly used on lathes or similar machinesfor holding 1323b 31/20 workpieces or tools, and in which the collethead is divided [50] Field of Search ..279/1 (ME), into Segments Spacedf each other by radial slots in which 1(5), 51, K sealing members arearranged to exclude oil and other foreign 56 R f d material from passingthrough the slots, and in which the slots 1 e I e are so formed that thesealing members may be passed UNITED STATES PATENTS lengthwise into andout of their operative positions in said 2,012,826 8/1935 Montgomery279/1(ME)UX slots from the outer face of the collet.

M. r a 22 Patented Nov. 10,1970 3,539,193

Sheet 2 015 Sheet 5 013 fam IN OR. 391W BY ATTORNEYS.

SEALS roa COLLETS In the accompanying drawings:

FIG. 1 is a sectional elevation of a collet embodying this invention,taken on'line 1-1, FIG. 2.

FIG. 2 is an end view of the collet.

FIG. 3 is a side view of a sealing member to be arranged betweensegments of the head of the collet to prevent passage of lubricant orcutting fluid lengthwise of the collet from the outer end thereof.

FIG. 4 is an end view of the sealing member shown in FIG. 3.

FIG. 5 is a central sectional elevation of a collet of modifiedconstruction as seen on line 5-5, FIG. 6.

FIG. 6 is an end view of the collet shown in FIG. 5.

FIG. 7 is a side elevation of a collet of another modified construction.the upper half of the view being a central section thereof.

FIG. 8 is an end view ofa collet shown in FIG. 7.

FIGS. 9 and 10 are a face view and an end view respectively of a scalingmember employed in the eollets shown in FIGS. 7 and 8.

The particular embodiment of this invention in the collet shown in FIGS.1-4 includes a body 12 of cylindrical shape which is arranged in aspindle l4 ofa machine and the body of the collet may be keyed to thespindle by any suitable means, such as a key (not shown) on the spindleextending into a slot or recess 17 in the body of the collet. The bodyis also provided with a threaded end 18 for connection with a draw tube19 for moving the collet back and forth relatively to the innerfrustoconical face 20 of the part 14 of the spindle.

The collet head is divided by longitudinal slots 22 extending inwardlyfrom the outer end thereof into a series of segments 24, four suchsegments being shown in the construction illustrated in FIGS. 1 and 2.The slots 22 extend into the body portion and form resilient fingerswhich urge the segments 24 thereof outwardly into contact with thefrustoconical bore 20 of the outer part of the spindle. The inner boreof the collet head may be of any suitable or usual construction forgripping a workpiece or tool but in the construction illustrated theinner faces of the segments 24 are provided with pads 26 which areremovably secured to the inner faces of the seg ments 24 by anysuitable, well known holding means, such for example as those shown inO'Connell U.S. Pat. No. 2,234,603 For this purpose each pad has anoutwardly extending projection 27 of dovetail shape which extendsoutwardly beyond the peripheral outer surface of the pad which engageswith the segments 24, this projection cooperating with the holdingmeans.

In the construction illustrated it is desired to provide seals whichprevent oil or other liquids from entering into the slots 22 and it alsohas been found desireable to have these sealing devices enter into theslots from the outer end of the head so that they are readily accessibleand can be inserted or removed with case. In the construction shown forthis purpose I have provided sealing members of rubber or other elasticmaterial which as shown in FIGS. 3 and 4 comprise flat or substantiallyrectangular parts 30 provided at one end thereof with substantiallysemicylindrical projections 31.

The flat sections 30 of the sealing members can be inserted into theslots 22 to fit snugly therein when the segments are separated, and theportions of the segments 24 adjacent to the slots are provided withholes or recesses which may be drilled into these segments to lie atopposite sides of the slots. These holes or recesses are formed toreceive the semicylindrical projections 31 and act as stops to limit theextent to which the scaling members may be inserted into the slots 22.It is understood of course that the slots are formed between the pads 26as well as between the segments 24 andconsequently when the sealingmembers are inserted into the slots 24 they will also extend between theends of the pads, as clearly shown in FIGS. 1 and 2. One end of eachofthe sealing members is provided with an inclined edge 32 which fitsagainst a part of the frustoconical bore 20 of the spindle. Thesesealing members may be made of any desired length and after they areinserted into the collet head from the outer face thereof, parts ofthese pads will extend inwardly beyond the inner surface of the pads andthese parts of the sealing members are then cut off and discarded sothat the sealing members will appear as shown in FIGS. 1 and 2.

In making these sealing members of a resilient material, such as rubberor neoprene, these sealing members will exert pressure against the padsand the segments so as to urge them upwardly against the frustoconicalsurface 20, thus supplementing the spring action of the portions of thebody between the slots 22.

It is of course an easy matter to insert the sealing pads into the endsof the slots from the head of the collet and also, if desired, to removethe seals from the collet. This can be easily done by inserting animplement into the back of a scaling member and pushing the sealingmember out, without opening the slots 22 to any greater extent thanpermitted by the drawn tube and frustoconical face 20. Consequently thepads can be easily removed and replaced after the seals have beenremoved. When the sealing members are removed the pads move toward theaxis of the collet to an extent necessary to permit the projections 27of the pads to move toward the axis of the collet sufficiently to clearthe holding means so that the projections 27 can be moved axially out ofthe collet with their pads. With the sealing parts arranged so that theycan be removed and inserted from the front of the collet head, theremoval and replacement of'pads 15 is greatly facilitated overconstructions in which the sealing members were inserted from the outersurface of the collet, in which access is prevented by the engagement ofthe segments with the frustoconical face 20 which would require thecollet to be removed from its draw tube and moved outwardly to provideaccess to the sealing member.

In the particular construction shown in FIGS 5 and 6, no pads areprovided and the segments 40 are required to grip the work or tool. Inthis case the sealing members 42 are similar in shape to those shown inFIGS. 3 and 4 except that the flat portions are required only to extendfrom the frustoconical surface to the inner surface of the segments.Otherwise the struc-,

tures in FIGS. 5 and 6 are similar to those shown in FIGS. 1 and 2except that the body is provided with three slots 4! forming threesegments.

In FIGS. 7l0 l have illustrated my improvement applied to a collet headof the type shown in FIGS. l5 of my pending U.S. Pat. application Ser.No. 572,844 now abandoned. filed Aug. 16, I966. In this construction thebody portion 50 is of cylindrical shape without any slots extending intothe same. The head of the collet is separate from the body portion andis divided by longitudinal slots 52 into a series of segments 54, foursuch segments being shown in FIGS. 7 and 3. These segments may beprovided with pads 56 suitably mounted on the segments 64. The segmentsjointly form a substantially frustoconical surface for cooperation witha frustoconical surface of a lathe spindle such as shown in FIGS. 1 and2.

The connection between the body of the collet and the segments of thehead is such as will allow longitudinal movement to be transmitted fromthe body to the segments and the segments are permitted to move radiallyrelatively to the body into and out of engagement with the work or toolto be held. This may be. effected by suitable releasable connectionsbetween the body and the segments. In die particular construction shownby way of example, the segments of the head are provided with outwardlyextending projections or keys 58 formed to fit into the annular grooves60 of the body. By means of this arrangement it will be noted that thesegments of the collet head may move relatively to a limited extent.

In order to prevent the segments of the collet from opening farther thannecessary when the collet is removed from the spindle, I preferablyprovide the segments with an annular groove 62 and a spring ring 64within this groove which ring does not extend to the bottom of thegroove and consequently does not interfere with the-normal radialadjustments of these 1 segments.

Three segments are provided with radially extending holes 66 formedacross the slots to receive resilient sealing members 68 which are orrubber or other resilient material and are therefore enabled to act assprings to open the collet when the same is moved forwardly, the holesand the sealing members being provided at the meeting edges of thesegments so as to urge the segments away from each other. These sealingmembers 68, in addition to acting as springs to move the segments awayfrom each other, also act as seals to prevent liquid or other materialfrom passing through the slots or spaces between the segments.

In this construction it is also very desirable to provide sealingmembers which are insertable from the outer face of the collet head. Forthis purpose I have provided sealing member 70 which includesubstantially flat parts 72 formed to enter into the slots between thesegments, and these sealing members are also provided at opposite facesthereof with semicylindrical parts 74 adapted to pass into holes drilledat the meetingcnds of the segments 54. The flat portions 72 of thesesealing members, which enter into the slots between adjacent segments,are formed so that they can be pushed into the slots to a sufficientextent to contact with the sealing members 68 and thus form a completeseal against any liquid which may pass into the slots of the collethead.

The sealing members 70 can be easily removed from the slots as describedin connection with FIGS. 1 and 2 so that different sealing members maybe positioned between the pads 56 which may be of different radialdimensions, thus requiring different sealing members 70. However,regardless of change of dimensions of the pads, the sealing members 68need not be removed since they will operate regardless of the dimensionsof the pads 56.

ln the construction shown in F I68. 7 and 8 the sealing members 68 mayremain in the segments while the pads 56 are changed from time to time.Consequently the sealing members 70 which are insertablc and removablefrom the outer face of the collet, can be readily inserted and removedwhenever pads of different sizes are required. When this collet isintended for use on tools or work of different diameters, the pads 56only are removed so that the sealing members 68 are not disturbed.

It will be understood that various changes in the details, materials andarrangements of parts which have been herein described and illustratedin order to explain the nature of the invention may be made by thoseskilled in the art within the principle and scope of the invention asexpressed in the appended claims.

lclaim:

1. A machine tool collet including:

a. a cylindrical body having a longitudinal axis;

b. a collet head at the outer end of said body having a front face;

c. a plurality of radial slots extending parallel to said longitudinalaxis for dividing said head into a plurality of segments each having aninner surface and an outer surface;

d. each of said segments having a recess adjacent each of said slotsextending rearwardly parallel to said longitudinal axis from said frontface of said collet head;

e. individual seal means insertable into said .slots from said outer endof said body;

f. each of said seal means having a flat body portion with front andrear edges and projections on each side of said body portion conformingto said recesses;

g. said projections cooperating with said recesses; and

h. each of said seal means extending radially inwardly from saidprojection to said inner surface.

2. A machine tool collet as in claim 1 and wherein: said projections andrecesses have arcuate cooperating surfaces.

3. A machine tool collet as in claim 2 and wherein: said projectionsextend rearwardly approximately one-half of the longitudinal dimensionof said seal means.

4. A machine tool collet as in claim 2 and wherein: each of said sealmeans extends radially outwardly from said projections to said outersurface. I

5. A machine tool collet as in claim 1 and including: interlocking partsbetween said segments and said body for holding said body and saidsegments against longitudinal movement relative to each other andpermitting limited radial movement of said segments relative to saidbody.

6. A machine tool collet as in claim 1 and including: a. work engagingpads secured to said inner surfaces of said segments; and b. each ofsaid seal means extending radially inwardly and coextensively with saidpads. 7. A machine tool collet as in claim 2 and wherein: saidprojections extend from the front edge of said seal rearwardly andending short 'ofthe near edge of said seal.

